It was a funny little man, short, inflated in its low part, and bicolor. He was floating beneath the surface. Our teacher in physics looked at us with a joyful eye, satisfied of the obtained effect, let a silence flow out and, while the little man feebly nodded in the aquarium, said, solemnly : «It is a ludion» (cartesian diver).

After the aquarium and the ludion came Archimedes, and we understood that the ludion was a kind of bienveillant servant of the great man. But what I did not realize then, is this greek-latin debt that we owed these words and these people. Or that Etruscans will come then back in our memoria.

The ludion, explains us French common dictionary ‘Larousse’, is this «hollow object or figurine, pierced in its lower part, which moves up or down in a liquid according the variations that the pressure exerces on its surface».

Such, this word has designed this object lately, in 1787, in the « Eléments de physique théorique et expérimentale » of the now forgotten Sigaud de Lafond, as unknown today than he was skilled then, in physics as in chirurgy. As his ludion, Sigaud de Lafond revolutionary period beneath the surface, and died because of the fire in his physics laboratory in Bourges, France.

«Ludion» comes from latin «ludio», and dictionaries tell us that it means «dancer» or «histrion».

The word, true, has two forms in latin : «ludio,-onis» et «ludius,-ii», and though classic dictionaries prefer this last one, which sound so much latin, the first word is older, and Livy (VII, 2, 4) gives us its key. In 364 BC, an epidemy of plague touched Rome. The idea was proposed going to Etruria and getting there artists who would perform in Rome «without any sung text» («sine carmine ullo») rythmned with a flute dances («tibicinis modos saltantes») meant to put in flight bad spells. These Etruscan dances thus impulse Roman Ludi scenici. And these artists, says Livy, were called «ludiones», from latin «ludi».

But those ludiones are not yet, at this time, histrions. The word « histrion » comes itself from the Etruscan «ister», which designs... the ludio. But in Rome, in the following decades, a histrion is the one who adds to dances a poetic improvisation inspired by heavy dirty style born in Fescennium, a big Etruscan village in Faliscan territory. These histrions evoluted from improvisation to preparation and gave then playlets that were called 'satyres', «saturae» meaning in latin «stuffed pieces», for they mixed song and mimes, always with the sound of the flute.

The histrion has stayed in modern French and English, and the ludion has thus reappeared, 230 years ago... beneath the surface. Strange destiny when we remember that Romans has always preferred the ground to the sea!

See wikipaedia article on
«Cartesian diver»

Publius Memmius Albucius